Conversion of fatty acids with several double linkages or of their glycerides into oleic-acidlike fatty acids or their soaps



Patented Sept. 12, 1922.

. CARL STIEPEL, or BERLIN, GERMANY, ASSIGNOR TO PERSAPOL- GESELLSCHAFT MIT BESCHRANKTER HAFTUNG, or HANOVER, GERMANY.

CONVERSION OF FATTY ACIDS WITH SEVERAL DOUBLE LINKAGEiS OR OF THEIR GLYCERIDES INTO OLEIC-ACIDLIKE FATTY ACIDS OR THEIR SOAPS.

No Drawing.

To all whom it may concern:

Be it'known that I, CARL STIEPEL, a citizen of the Republic of Germany, residing at Bayreutherstrassc 18, Berlin, (S2, Ger-' many, have invented a certain new and useful improvement in the conversion of fatty acids with several double linkages or of their'glycerides into oleic-acidlike fatty acids or their soa s (for which I have filed applications 1n ierma-ny May 6, 1914, and Great Britain April 13, 1920, No. 10335 of 1920), of which the following is a specification.

The Varrentrapp reaction deals with a process of converting oleic acid into palmitic acid by melting with an excess of caustic potash.

In carrying this process'i-nto effect oleic acid, for example, is heated in iron vessels and evaporated with 1.6 times a quantity of caustic lye of 43 B., that is to say, with about four times the quantity of lye than is requisite for the saponification proper. In this operation the temperature is raised to 320 C. The conversion of the oleic'a-cid into palmitic acid takes place with a lively generation of hydrogen.

If the alkali used in the place of potash is sodium hydroxide, it is necessary to make simultaneous use of parafiins.

A ground for the failure of productivenes's of the above reaction in regard to commercial use'may be stated apart from its high cost, to reside in the danger occasioned-by the development of the hydrogen. Not

touched upon need here be the question whether the term oleic acid used should be held to mean oleic acid in the chemical sense or whether the term oleic acid as is frequently the case should in fact be deemed valid for the Varrentrapp reaction as one generally embracing all liquid unsaturated fatty acids of fats and oils. At any rate the idea of the intermediary formation of fatty acids with several dou'ble linkages or of their glycerides in oleicand like; fatty acids or their soaps in a technical operationis not included in the Varrentrapp reaction since its object is solely the production of solid palmitic acid.

In contradistinction therefrom the process according to this invention has for its object the technical conversion of fatty acids with several double linkages or of their Application filed September 14, 1920. Serial No. 410,212.

glycerides into oleic acid like fatty acids, accompanied in most cases as against the effect of the Varrentrapp reaction, b a lower ng of the solidification point oftl ie fatty acids. Treating, for example, cotton seed oil, the fatty acid of which has an iodine value of 102 and a titer of 345 C., according to this invention, the fatty acid after treatment was found to have the following analytical data, titer 265 0., iodine value 62. The latter figure shows a. reduction of the more strongly unsaturated fatty acids down to an oleicacid like fatty acid and the lowering of the titerwhich must likewise be attributed to this conversion into oleic acid far' reaching reduction to solid fatty acids did not take place. This study of the problem of converting fatty acids with several double linkages or their glycerides into oleic acid like fatty acids or their soaps has now led to the discovery that such a conversion may be brought about by heating the soaps of these fatty acids without a material excess of alkali for some considerable time in closed vessels to temperatures from 21()250 C. without evaporation to dry- The defects of the Varrentrapp reaction above mentioned as regards commercial practicability are thus avoided. The cost of the process is materially lessened .and the development of hydrogen is entirely counteracted.

By this conversion, technically possible without drawbacks, of fatty acids with several double linkages or of their glycerides into oleic acid like fatty acids or their soaps, a materially higher technical usefulness is opened up both for the soaps which are much harder and therefore of more use in the manufacture of soap than the soaps of the original oils and the fatty acids.

Example: 100 parts of sesame oil or sesame oil fatty acids are saponified with 40 like fatty acids points to the fact that a more parts of sodium hydroxide of 45 B. and I then heated in a suitable apparatus for four hours to 245 C. The result is a soap hearing in every respect the character of an oleic acid soap. After splitting it by meansof a titer of 25 Cfand an iodine value of 106, the fatty acid of the soap treated has a standard of only 14 C. for an iodine "alue of 78.

In the place of caustic potash use may be made also of the alkaline earths for saponitying purposes. After the treatment it is possible to effect a transposition with alkali carbonates for the purpose of obtaining Water soluble soaps in a known manner.

\Vhat I claim and desire to protect by Letters Patent is 1. A process for the conversion of fatty acids with at least two double linkages. or of their glycerides into oleic acid-like fatty acids, or their soaps, in which the material is first saponified and thereafter the product is heated to dryness Without evaporation at a temperature between 210 and 250 1 without a material excess of alkali or alkaline earths.

2. A process for the conversion of fatty acids with at least two double linkages, or of their glycerides. into oleic acid-like fatty acids, or their soaps. in which the material is first saponified and thereafter the product is heated, to dryness without evaporation at a temperature between 210 to 250 F., without a material excess of alkali or alkaline earths. and thereafter recovering the fatty acids from the product by means of a mineral acid.

In testimony whereof I have affixed my signature in presence of two witnesses.

, CARL STIEPEL.

\Vitnesses Anna; PRUYN, FRITZ KijHNE. 

